This invention relates generally to integrated circuits, and more specifically to a method for coating an integrated circuit substrate with a layer of material.
Integrated circuit fabrication requires various materials to be spin-coated on to an integrated circuit substrate. For example, integrated circuit substrates are routinely spin-coated with dielectric layers, such as polyimide and spin-on-glass. Moreover, the lithographic patterning processes that are used throughout the fabrication process require the integrated circuit substrate to be spin-coated with various resist layers. It is essential that the spin-coating process provide a uniform and defect free layer of material on the integrated circuit substrate, otherwise, the reliability and functionality of the resulting integrated circuits will be adversely affected. In order to insure that a uniform and defect free layer of material is achieved, current spin-coating processes dispense a large volume of material, which is in excess of what is actually required, on to the integrated circuit substrate. The excess material is subsequently spun off the integrated circuit substrate, and thus is lost or wasted. Obviously, this process can be quite costly, especially when a material costing several hundred dollars per gallon is being used to coat the integrated circuit substrate. Moreover, there is also the added cost of treating and disposing of the spun off material. Accordingly, a need exists for a method that can coat an integrated circuit substrate with a uniform and defect free layer of material, while minimizing the volume of material required to be dispensed on to the integrated circuit substrate.